scholarly journals Ecology ofPeltoperla arcuataandTallaperla maria(Plecoptera: Peltoperlidae) at the Fernow Experimental Forest, Tucker County, West Virginia

1995 ◽  
Vol 102 (3-4) ◽  
pp. 151-168 ◽  
Author(s):  
Kevin A. Yokum ◽  
Ted R. Angradi ◽  
Donald C. Tarter
Keyword(s):  
Life History ◽  
West Virginia ◽  
Life Cycles ◽  
Base Flow ◽  
Order Stream ◽  
Egg Diapause ◽  
Specific Distribution ◽  
Stream Size ◽  
Species Specific ◽  
Fernow Experimental Forest

We examined the abundance, life history, and production of the stonefliesPeltoperla arcuataandTallaperla maria(Plecoptera: Peltoperlidae) in four forested headwater streams at the Fernow Experimental Forest, Tucker County, West Virginia.Peltoperla arcuatawas most abundant in the smallest watersheds (<100 ha), and was present at all sites.Tallaperla mariawas most abundant in watersheds >200 hectares (ha), was restricted to sites with a base-flow alkalinity of >2 mg L-1CaCO3, and was the dominant peltoperlid only at sites with an alkalinity >15 mg L-1. We conclude that water chemistry overrides stream size as a determinant of species-specific distribution of Fernow peltoperlids. Both taxa had semi-voltine life cycles with an 18-month naiadal period following a 6-month egg diapause. Emergence was during May-July for both species.Peltoperla arcuatahad about 15 instars;T. mariahad about 14 instars. Peltoperlid production was highest (509 mg m-2y-1) in a 128 ha watershed where onlyP. arcuatawas collected;P. arcuataproduction was lowest (17 mg m-2y-1) in a 4th order stream (1536 ha).Taltaperla mariaproduction was highest (271 m-2y-1) in a 257 ha watershed partially underlain by limestone. Production across streams was higher forP. arcuata(205 mg m-2y-1) than forT. maria(91 mg m-2y-1).

Routine identification of four sympatric species of calanoid copepods Pseudocalanus spp. in the Atlantic Arctic using a species-specific polymerase chain reaction

2020 ◽  
Vol 48 (1) ◽  
pp. 62-72
Author(s):  
E. A. Ershova
Keyword(s):  
Polymerase Chain Reaction ◽  
Life Cycles ◽  
The Arctic ◽  
Relative Distribution ◽  
Chain Reaction ◽  
Specific Polymerase Chain Reaction ◽  
Routine Identification ◽  
Polymerase Chain ◽  
Species Specific ◽  
Plankton Communities

Сalanoid copepods of the genus Pseudocalanus play an important role in the plankton communities of the Arctic and boreal seas, often dominating in numbers and constituting a significant proportion of the biomass of zooplankton. Despite their high presence and significance in the shelf plankton communities, species-specific studies of the biology of these are significantly hampered by extremely small morphological differences between them, especially at the juvenile stages, at which they are virtually indistinguishable. In this paper, we describe a new, routine and low-cost molecular method for identifying all Pseudocalanus species found in the Atlantic sector of the Arctic: the Arctic P. acuspes, P. minutus and the boreal P. moultoni and P. elongatus, and apply it to describe the relative distribution of these species in four locations of the Arctic and sub-Arctic. With this method, species-specific polymerase chain reaction (ssPCR), mass identification of individuals of any developmental stage, including nauplii, is possible. This method can serve as an excellent tool for studying the species-specific biology of this group, describing their life cycles, as well as monitoring changes in Arctic marine ecosystems under the influence of changing climate.

scholarly journals Longitudinal zonation of larval Hydropsyche (Trichoptera: Hydropsychidae): abiotic environmental factors and biotic interactions behind the downstream sequence of Central European species

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Márk Ficsór ◽  
Zoltán Csabai
Keyword(s):  
Environmental Factors ◽  
Biotic Interactions ◽  
Life Cycles ◽  
Longitudinal Distribution ◽  
Central European ◽  
European Species ◽  
Longitudinal Gradients ◽  
Species Specific ◽  
Behavioural Aspects ◽  
Abiotic Environmental Factors

AbstractThe aim of this review is to summarize the literature knowledge about how abiotic environmental factors and biotic interactions affect the sequentially overlapping longitudinal distribution of Central European species of the net-spinning freshwater caddisfly larvae of the genus Hydropsyche (Trichoptera: Hydropsychidae). In this relation, several physical and chemical parameters of water are discussed, as well as different species-specific traits, behavioural aspects and the interaction of coexisting species. Longitudinal gradients of river networks, especially annual temperature range, flow velocity and the particle size of suspended food material play a crucial role in forming the downstream succession of characteristic species, while increased levels of organic pollution, nutrients, salinity and heavy metals facilitates the presence of more tolerant ones. Several species-specific traits, such as respiration range, net-building frequency, head capsule size or optimal net-building velocity correlate with the position of a given species in the sequence. Coexistence of species with similar ecological demands in the overlapping zones of distribution is facilitated by differences in feeding and net-building habits, microhabitat preferences and staggering life cycles, but complicated at the same time by means of inter- and intraspecific territorial behaviour, such as fighting for the ownership of larval retreats or the practice of stridulation.

scholarly journals Effect of NaCl on seed germination in some Centaurium Hill. Species (Gentianaceae)

2007 ◽  
Vol 59 (3) ◽  
pp. 227-231 ◽  
Author(s):  
S. Zivkovic ◽  
M. Devic ◽  
B. Filipovic ◽  
Z. Giba ◽  
D. Grubisic
Keyword(s):  
Life History ◽  
Salt Tolerance ◽  
Seed Germination ◽  
Gibberellic Acid ◽  
White Light ◽  
The Other ◽  
Distilled Water ◽  
Nacl Concentration ◽  
History Of ◽  
Species Specific

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .

scholarly journals The Domestication of Evolution

1983 ◽  
Vol 10 (4) ◽  
pp. 283-292 ◽  
Author(s):  
Raymond P. Coppinger ◽  
Charles Kay Smith
Keyword(s):  
Life History ◽  
Sexual Maturity ◽  
Domestic Animals ◽  
Stable Environment ◽  
In The Wild ◽  
Species Specific

A coming ‘Age of Interdependent Forms’ seems destined to mark the success of what could be called ‘despecialized/interspecific fitness’ among neotenic strains (perpetuating juvenile traits) of species such as humans and domestic animals. Humans as well as the first domesticants underwent a neotenic evolution in the wild during the repeated interglacial periods which, acting on a number of mammalian forms, selected against adult species-specific ancestral adaptations to a stable environment. Neotenic species continue to look and behave more like ancestral youths than adults—even after sexual maturity and throughout their life-history. As they retain lifelong youthful dependency motivations, they can easily, under suitable conditions, become interdependent forms. By the time of melting of the last Pleistocene glacier, all the domestic partners had already become more dependency-prone than formerly, and were behaviourally despecialized enough to form the alliance that is now changing the order of Nature.

scholarly journals Endocrine Control of Life-Cycle Stages: A Constraint on Response to the Environment?

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Jerry D. Jacobs ◽  
John C. Wingfield
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Control Systems ◽  
Life Cycles ◽  
Environmental Cues ◽  
Endocrine Control ◽  
Theoretical Approaches ◽  
Life Cycle Stages ◽  
Wide Range ◽  
Breeding Seasons

Abstract Most organisms live in seasonal environments that fluctuate on a predictable schedule and sometimes unpredictably. Individuals must, therefore, adjust so as to maximize their survival and reproductive success over a wide range of environmental conditions. In birds, as in other vertebrates, endocrine secretions regulate morphological, physiological, and behavioral changes in anticipation of future events. The individual thus prepares for predictable fluctuations in its environment by changing life-cycle stages. We have applied finite-state machine theory to define and compare different life-history cycles. The ability of birds to respond to predictable and unpredictable regimes of environmental variation may be constrained by the adaptability of their endocrine control systems. We have applied several theoretical approaches to natural history data of birds to compare the complexity of life cycles, the degree of plasticity of timing of stages within the cycle, and to determine whether endocrine control mechanisms influence the way birds respond to their environments. The interactions of environmental cues on the timing of life-history stages are not uniform in all populations. Taking the reproductive life-history stage as an example, arctic birds that have short breeding seasons in severe environments appear to use one reliable environmental cue to time reproduction and they ignore other factors. Birds having longer breeding seasons exhibit greater plasticity of onset and termination and appear to integrate several environmental cues. Theoretical approaches may allow us to predict how individuals respond to their environment at the proximate level and, conversely, predict how constraints imposed by endocrine control systems may limit the complexity of life cycles.

Anuran life history plasticity: Variable practice in determining the end-point of larval development

2010 ◽  
Vol 31 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Patrick Thomas Walsh
Keyword(s):  
Life History ◽  
Developmental Stages ◽  
Life Cycles ◽  
Developmental Phase ◽  
Larval Phase ◽  
End Point ◽  
Anuran Amphibians ◽  
Individual Fitness ◽  
Metamorphic Climax ◽  
Size At Metamorphosis

AbstractPlasticity in the timing of life history events and their impact on individual fitness, particularly the timing of and size at metamorphosis in animals with complex life cycles such as anuran amphibians, has long been of interest to ecologists. For different studies on life history plasticity to be comparable, there must be clearly defined and commonly agreed transition points, but it is unclear how consistently this is being performed in studies using anuran amphibians. In a review of 157 published studies, I found considerable variation in defining the end point of the larval phase. While a slight majority used the emergence of the forelimbs as the conclusion of the larval phase, some used a period within the developmental phase of metamorphic climax and others used the resorption of the tail. Studies included in this review, that assessed the same life history variable at two different developmental stages, reported some differences in results depending on which developmental stage was used. Recent evidence also shows that metamorphic climax is itself a period which can vary with environmental conditions, but, even in studies that included part or all of metamorphic climax in the larval phase, the treatment of individuals during metamorphic climax was not reported. Therefore, I argue that life history studies on anuran amphibians should distinguish the following phases: larval, metamorphic climax, juvenile, adult; that the end of the larval phase is best defined in ecological studies by forelimb emergence and that conditions under which individuals undergo metamorphic climax should be fully described.

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